Gunnar and Matthew Nelson, the 23-year-old twin sons of the late Rick Nelson, said they are glad they were able to avoid the "teen idol" trap that caught their father. Gunnar said their father "had problems with teen idol stigma as long as we could remember. People were always coming up and asking, `Are you Ricky Nelson? I grew up with you on your TV shows.' " Gunnar, who with his brother now make up the rock group Nelson, said, "Those people never let go of that. They couldn't even let him drop the `y' from Ricky, because it would have made them feel older." The Nelson twins said they still follow their father's advice to "believe in what you're doing, keep doing it and keep your sense of humor." And there was one more piece of his advice the twins say they follow: " `Write your own songs!' So we did."